Measured and calculated distributions of deep defect states in hydrogenated amorphous silicon: Verification of deep defect relaxation dynamics

1993 ◽  
Vol 71 (4) ◽  
pp. 597-600 ◽  
Author(s):  
Fan Zhong ◽  
J. David Cohen
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Relaxation Dynamics ◽  
Defect States ◽  
Deep Defect ◽  
Hydrogenated Amorphous ◽  
Silicon Verification ◽  
Defect Relaxation

Recombination Process in the As-Deposited State of Hydrogenated Amorphous Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
Jong-Hwan Yoon
Keyword(s):  
Amorphous Silicon ◽  
Defect Density ◽  
Energy Levels ◽  
Hydrogenated Amorphous Silicon ◽  
Recombination Process ◽  
Defect States ◽  
Deep Defect ◽  
Recombination Centers ◽  
Hydrogenated Amorphous ◽  
Deposition Conditions

Intrinsic deep defect-related recombination process has been studied in a series of undoped hydrogenated amorphous silicon(a-Si:H) films grown under different deposition conditions. Steady-state photoconductivity (σph) was measured as a function of deep defect density Nd, Urbach energy Eu, and dark Fermi energy Ef. It was found that σph strongly depends on these parameters while Ef- stays at the energy levels lower than 0.82 eV below Ec, but it is nearly independent of those while Ef stays at above 0.82 eV. These behaviors were found to be independent of the sample deposition conditions. These results indicates that subgap defect states enclosed by E=0.82 eV and Ef are the dominant recombination centers.

Theoretical Studies of Structure and Doping of Hydrogenated Amorphous Silicon

2011 ◽  
Vol 1321 ◽  
Author(s):  
Bin Cai ◽  
D. A. Drabold
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Theoretical Studies ◽  
Defect States ◽  
High Impurity ◽  
Bond Center ◽  
B Doping ◽  
Hydrogenated Amorphous ◽  
Center Site

ABSTRACTIn a-Si:H, large concentrations of B or P (of order 1%) are required to dope the material, suggesting that doping mechanisms are very different than for the crystal for which much smaller concentrations are required. In this paper, we report simulations on B and P introduced into realistic models of a-Si:H and a-Si, with concentrations ranging from 1.6% to 12.5% of B or P in the amorphous host. The results indicate that tetrahedral B and P are effective doping configurations in a-Si, but high impurity concentrations introduce many defect states. For a-Si:H, we report that both B(3,1) and P(3,1) (B or P atom bonded with three Si atoms and one H atom) are effective doping configurations. We investigate H passivation in both cases. For both B and P, there exists a “hydrogen poison range” of order 6 Å for which H in a bond-center site can suppress doping. For B doping, nearby H prefers to stay at the bond-center of Si-Si, leaves B four-fold and neutralizes the doping configuration; for P doping, nearby H spoils the doping by inducing a reconstruction rendering initially tetrahedral P three-fold.

Defect States in Hydrogenated Amorphous Silicon-Sulphur Alloys by ESR and PAS

1991 ◽  
Vol 219 ◽  
Author(s):  
Gaorong Han ◽  
Jianmin Qiao ◽  
Piyi Du ◽  
Zhonghua Jiang ◽  
Zishang Ding
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Spin Density ◽  
Molecular Hydrogen ◽  
Annealing Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Sulphur Content ◽  
Defect States ◽  
Hydrogenated Amorphous

ABSTRACTWe have presented ESR and PAS measurements for a series of a-SiS:H and a-Si: H films deposited by glow discharge at different parameters. The spin density in a-SiS:H alloys measured by ESR is essentially independent of the sulphur content, while the density of defects measured by PAS increases significantly with the increasing of sulphur content. The ESR signals in a-SiS:H alloys strongly depend on both annealing and illumination. The spin density increases up to 540°C and then decreases with raising annealing temperature for a-SiS:H and a-Si:H alloys. The results suggest that some new defects such as molecular hydrogen and microvoids are appeared when addition of sulphur to a-Si:H films.

Charged defect states in intrinsic hydrogenated amorphous silicon films

1994 ◽  
Vol 76 (4) ◽  
pp. 2260-2263 ◽  
Author(s):  
Mehmet Güneş ◽  
Christopher R. Wronski ◽  
T. J. McMahon
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Films ◽  
Charged Defect ◽  
Defect States ◽  
Hydrogenated Amorphous

Stability in Amorphous Silicon

1987 ◽  
Vol 95 ◽  
Author(s):  
Z E. Smith ◽  
S. Wagner
Keyword(s):  
Electron Spin Resonance ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Thermal Recovery ◽  
Defect States ◽  
Spin Resonance ◽  
Resonance Data ◽  
Electron Spin Resonance Data ◽  
Gap States ◽  
Hydrogenated Amorphous

AbstractThe experimental phenomena associated with light-induced degradation and thermal recovery of hydrogenated amorphous silicon (a-Si:H) films are reviewed, with special emphasis on the limitations of each experimental technique. When several techniques are used in concert, a fuller picture emerges. Recent experiments suggest different positions in the band-gap of the paramagnetic-associated defect states (the dangling bonds) for doped and undopedfilms; this information can be combined with conductivity, sub-bandgap optical absorption and electron spin resonance data to yield a model for the density of gap states (DOS) in a- Si:H, including how the DOS changes upon illumination and annealing.

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